SPF, DKIM and DMARC alignment, warm-up, and the content patterns that route a legitimate message to spam.
SkillScore96Maintained
Automatic
◆Marketing & Content pack
Last verified 8/3/2026
What it changes
Passed 23 of 24 test cases with the skill, and 22 of 24 without it.
Without skill92%
With skill96%
Checks it passed that the model alone missed
Recommends a starting volume between 20 and 100 emails
1 fixed22 passed either way1 still failing0 broke
Pass-rate lift
+4 pp
Tokens
+11%
Agent turns
0%
Response time
+13%
Model gemini-3.6-flashMeasured 8/3/2026v123 of 24 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
A test case the skill fixed. Same model, same prompt, with and without the skill.
Prompt
We just purchased a brand new dedicated IP address and domain to send 100,000 monthly newsletters. To avoid immediately ruining our reputation, what is a standard recommended maximum number of emails to send on Day 1 of the warm-up?
What was checked, without and with the skill
Checked
Without skill
With skill
Recommends a starting volume between 20 and 100 emails
Missed
Passed
case-08 · gemini-3.6-flash · 8/3/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md4 linessingle file
email-deliverability
SPF, DKIM and DMARC alignment, warm-up, and the content patterns that route a
legitimate message to spam.